The present application relates to a diffusion sheet, a method of manufacturing the diffusion sheet, and a backlight and a liquid crystal display device that are provided with the diffusion sheet. Specifically, it relates to a diffusion sheet with structures each in a convex shape formed on a surface thereof.
In the past, a variety of optical sheets are used for backlights mounted in liquid crystal display devices. Among such a variety of optical sheets, one of the most important ones includes diffusion sheets. As such a diffusion sheet, those widely used are provided with a sheet formed of a resin material, such as polyethylene terephthalate, and a diffusion layer formed by applying a resin composition having resin beads dispersed therein on a sheet and curing it (for example, refer to Japanese Unexamined Patent Application Publication No. 2000-89007). In a diffusion sheet having such a configuration, light incident from a light source is diffused and collected by resin beads contained in the diffusion layer.
In recent years, with the improvement in the aperture ratio of liquid crystal panels, lens sheets have been desired to be replaced with diffusion sheets. However, the diffusion sheets in the past described above may be insufficient in luminance, and improvement in the luminance of diffusion sheets is strongly desired.